when i type this formula into the cell, it automatically turns into 34700,
rather than keeping the actual criteria there??


That's fine; Excel's dates (and times) are just specially formatted
numbers. To see for yourself, type the date in some random cell then format
it using the 'comma' style. The challenge is to be able to have the date in
a format you can understand (1/1/05) and Excel can use to compare (34700).
Roger's suggestion to keep the date in a separate cell should work fine, or
you can use the DATE function mentioned earlier.